0)1 an Experimental Modification of van der Waalss Equation. 127 
r is now evaluated from tables for various values of the parameter /3, and 
the saturation constants then obtained. Even v^ith tables the calculations 
are somewhat laborious, and it was found to be much easier to derive the 
modified constants from the table of unmodified constants referred to 
above. It is evident that the modification now introducted does not 
affect in any way the relative values of the saturation volumes ; hence 
if TI and 0 are the ordinary van der Waals saturation pressure and 
temperature for any pair of volumes, and tt and ^ represent the modified 
constants, we find — 
If equation (14) is written in the form — ■ 
log, 109 = log, 10^-1 + -^ 
it can be solved by inspection from a table of natural logarithms ; tt is 
then obtained from the known ratio Proceeding in this way, the 
following table of modified constants was obtained. 
Table II. 
Saturation Constants according to the Modified Equation. 
3-. 
TT. 
0-4964 
0-0005275 
0-3698 
2506 
2-704 
0-0004 
0-5493 
0-002460 
0-3777 
592-6 
2-646 
00017 
0-5980 
0-007736 
0-3864 
203-6 
2-587 
0-0049 
0-6430 
0-01877 
0-3960 
89-15 
2-525 
0-01122 
0-6850 
0-03807 
0-4068 
45-98 
2-459 
0-02175 
0-7245 
0-06795 
0-4188 
26-61 
2-388 
0-03758 
0-7615 
0-1103 
0-4326 
16-73 
2-312 
0-05977 
0-7966 
0-1665 
0-4485 
11-18 
2-230 
008946 
0-8298 
0-2376 
. 0-4672 
7-811 
2-140 
0-1280 
0-8614 
0-3244 
0-4896 
5-643 
2-042 
0-1772 
0-8916 
0-4272 
0-5174 
4-173 
1-933 
0-2396 
0-9204 
0-5463 
0-5534 
3-128 
1-807 
0-3197 
0-9480 
0-6815 
0-6034 
2-349 
1-657 
0-4257 
0-9745 
0-8328 
0-6841 
1-727 
1-462 
0-5790 
1-0000 
1-0000 
1-0000 
1-000 
1-000 
1-000 
* If, as is in the meantime assumed, 6 is a constant. 
